Method and apparatus for weatherproofing aggregate and the like



INVENTOR.

ATTORNEY.

3 Sheets-Sheet 1 J. E. HALL Filed May 8. 1941 a w o 0 m W/o o o 0 o o 00 0 o March 16, 1943.

METHOD AND'APPARATUS FOR WEATHERPROOFING AGGREGATE AND THE LIKE J. E.HALL 2,313,820 METHOD AND APPARATUS FOR WEATHERPRQOFING AGGHEGATE ANDTHE LIKE March 16, 1943.

Filed May 8, 1941 3 Sheets-Sheet 2- March 16, 1943. J. E. HALL 2,313,820

METHOD AND APPARATUS FOR WEATHERPROOFING AGGREGATE AND THE LIKE FiledMay 8, 1941 3 Sheets-Sheet 3 RAW AGGREGATE (QUARRY summon SCREENS (wsTmmnmme mu) BUPPLY 1am SUPPLY an: svppn an: "amass" A "manual" "SMALL" 1A vI mum; HEATING, mm-ms 0mm cmmm clmmzn mnmni unusu l nm'mc nm'rmamm'nvs cmxszn cmmasn cnmsm TWURE rmmzmmz TME'RATURE" nzwcme REDUCINGmmcm; cnmamn cmmsnn cmmm memmmc IJIPRBGHATING mnmcmlm 0mm" 0mm cmmamzwarms wsrme msmmc 0mm QHAMBER CHAMBER coouuc 000mm 000mm CHAMBER CHAMBER0mm STORAGE swam-1 swam:

INVENTOR. F 3 BY .Tamu 5/06 1%! ATTORNEY.

Patented 16, 1943 s PATENT OFFICE METHOD AND APPARATUS FOR WEATHER-PROOFING AGGREGATE AND THE LIKE James Elliott Hall, Columbus, OhioApplication May 8, 1941, Serial No. 392,516

8 Claims.

The invention relates to a method and apps.- ratus' for weatherprooflngaggregate and the like.

It is an object of the present invention to provide a method forweatherproofing aggregate and the like wherein the aggregate is heatedto substantially eliminate all moisture therefrom and then, before theaggregate has cooled sufficiently to reabsorb moisture, treating theaggregate with a suitable weatherproofing agent to seal each particle ofaggregate from the moisture in the atmosphere,

It is a further object to dehydrate the aggregate and then next whilethe aggregate is in the dehydrated state impregnating the pores thereofwith a suitable weatherproofing agent.

his a further object of the invention to provide a method forweatherproofing aggregate and the like wherein the aggregate is heatedto a suitable temperature to substantially eliminate all moisturetherefrom, and then, before the heated aggregate is exposed toatmospheric air,

treating the same with asuitable weatherproofing agent to seal eachparticle of aggregate from moisture and the atmosphere.

ther object, in some instances, to cause the aggregate to be agitatedduring the heating thereof. It is a further object of the invention tocause hrelatively cool dehumidified air to pass over the being dependenton variable factors such as, the

temperature of the treated aggregate and the volatilization temperatureof the weatherproofing agent.

It is a further object of the invention first to grade the aggregate, tobe coated, as to size, and then treat each of the grades of aggregateseparately, such treating including dehydrating the graded aggregates bycausing each of the pieces of the aggregate to be subjected to heatwhile in a thin layer, then while the aggregates are in a dehydratedstate and before the same have cooled to such a degree as to absorbmoisture,

impregnating the aggregates with a suitable weatherproofing agent, andthen remix the graded aggregates with one another.

Another object of the invention is to provide a machine for carrying outthe aforementioned steps, said machine including a plurality ofchambers, each chamber, and the mechanism therein, being capable ofexecuting a step in the In carrying out the above object it is afurprocess, means being provided for advancing the aggregate through thechambers and from one chamber to the next.

It isa still further object to provide a machine in which the chambersare. disposed one above the other, the aggregate being fed into themachine at the top thereof and advanced from one chamber to the nextby'gravity.

It is another object of the invention to provide a machine suitable forvehicular mounting, to make the same mobile, thus facilitating movementof the machine.

Other and further objects and advantages will be apparent'from thefollowing description, reference being had to the accompanying drawingswherein a preferred form of embodiment of the present invention isclearly shown.

In the drawings:

Fig. 1 is a side view, in section, of a vehicular machine, or plant,used in the weatherproofing of aggregate;

Fig. 2 is an end view of the machine shown in Fig. 1; and,

Fig. 3 is a flow chart showing the various steps in the process, in theorder of execution thereof.

Referring to the drawings, a preferred form of plant 20 is shown. 'Sucha plant is generally utilized for treating aggregate with, for example,a bituminous compound, to qualify the same as a basic ingredient in themanufacture of bituminous concrete, and the like. 'The plant 20 ispreferably carried by a truck 2|, thus providing a vehicular plant thatcan readily be moved to any desired location, for example, a quarry orgravel pit.

The plant 20 includes a plurality of separate, rectangular chambers, oneof such chambers 23 being at the top of the plant. An endless metallicconveyer, such as: a belt 21, is disposed within the chamber 23 andextends, substantially the entire length and breadth of the chamber. The1 belt 21 is carried by a plurality of sprockets 29 the mechanismtherein, since when the belt 21 is removed, there is but one shaftextending across the chamber. The sprockets 29 are suitably driven,preferably by external means (not shown), to cause the belt 21 to moveslowly in a counterclockwise direction.

A feeding hopper 25 is disposed on the top of, and adjacent one end ofthe chamber 23 and is utilized as a means for feeding aggregate, such asa mineral aggregate, to the belt 21 within the chamber. The hopper 25may be provided with,

a metering device 26, in the form of a spurred shaft, for feeding theaggregate through the h-opper at a desired rate ,of speed. The belt 21extends beneath the egress of the hopper 25 and as aggregate is fed fromthe hopper 25, it falls directly upon the belt 21. An adjustableleveling blade 3|, extending completely acrossand slightly above thebelt, is disposed in the path of the moving aggregate and levels thesame so that only a desired thickness of aggregate passes through thechamber 23 onto the belt 21.

A suitable number of adjustably mounted burners 33, are disposedwithinthe chamber 23, adjacent the top thereof, and are preferably adjusted sothat the flames emitted therefrom are inclined downwardly. Thus theouter ends of the flames, which curl upwardly, to some-extent, do notimpinge on, and thereby carbonize the top of the chamber. The burners 33are also adjustable in the vertical plane so that the flames can bepositioned any desired distance from the moving aggregate. Preferably,oil'is utilized as the fuel for the burners 33 andis burned in a.luminous flame to providethe maximum radiant heat therefrom. In thismanner the aggregate on the belt 21 is exposed to an open and preferablyluminous flame and consequently is well heated and thoroughly dried. 1

Secondary air for the burners 33 is supplied by a-suitable number ofopenings 35, positioned ad- Secondary air for the burners 33, in chamber3 4|, is supplied by a forced draft dehumidifying unit 49, ofconventional design, which exhausts dehumidified air into the chamber45. This air passes over the hot dry aggregate on belt 41, and ispreheated while effectively reducing the temperature of the aggregate.The heated and dehumidified air then enters the chamber 4! through aplurality of apertures 5| of graduated size, to more evenly distributethe air .to the burners 38, and also through the opening around thechute 45. The excess air and products of combustion, of burners 38, areexhausted from chamber 4| by a suitable exhaust fan 53. Thus it isapparent that the dehumidified air passes countercurrent to the movementof the aggregate in chamber 49, to reduce the temperature thereperaturereduction chamber 46 is' discharged.

from the belt 43 onto an inclined chute 55 which delivers the same to aconveyer, such as a belt 51, within a chamber 59. The belt 51 travels ina clockwise direction and passes over and under suitably disposedsprockets 6| which causes the belt to be depressed in the centralportion thereof andto pass through a shallow tank or vat 93. The vat 63contains a treating compound, such as a material impervious to moisturesuch as ahydro-carbonaceous material, for example, caoutchouc (C5Ha)z,asphalt, bituminous compounds and I preferably employ a bituminouscompound.

' In this manner the hot dry aggregate is imthe aggregate to a secondconveyer, such as belt 43, which is disposed within chamber 4|. The belt43 is similar in all respects and is caused to move in the same manneras belt 21. The belt 43 travels in a clockwise direction to convey theaggregate through the chamber 4| (the function of chamber 4| will bedescribed hereinafter) to the opposite end thereof where the aggregateis dropped upon an inclined chute 45 communicating with a third chamber49. The chute 45 delivers the aggregate to a belt 41 which is similar inall respects to the aforementioned belts and travels in acounterclockwise direction within the chamber 46. It will be observedthat chamber 4| is also provided with burners 38, ad-

iacent the top thereof and similar to the burners 33. Thu s,theaggregate is heated in chamber '23, agitated, due to the fall down chute39 The agitaand further-heated in chamber 4|. tion of the aggregatecauses different surfaces thereof to be exposed to the open flames andin this. manner provides more thorough dehydration of the aggregate.

mersed in the treating compound for a predetermined period of timedependent on the longitudinal rate of movement of the belt. The belt 51emerges from the vat 63 and travels parallelly thereover for asubstantial distance to permit the surplus compound to drain from theaggregate into an extended and inclined portion 64 of the vat 53.

Preferably the bitumen used in vat 63 is .cut with a non-inflammablesolvent to lower the viscosity thereof and thereby cause more thoroughimpregnation of the bitumen solution into the usually cellular structureof the aggregate. The bituminous solution is supplied from a tank, orother means, external of the chamber 59. A pump may be provided tocirculate the solution, through suitable strainers and coolingapparatus, from the vat 63 to the tank to cool the same. This may benecessary in some instances since the hot aggregate immersed in thesolution causes the solution to be heated to a temperature beyond thatdesired.

In some cases the bituminous compound is used without a solvent orcutting agent, In this event a burner 6| is provided for thevat 53 toheat the compound to liquidity when operation of the plant'is initiated;thereafter the hot aggregate maintains the liquidity of the compound,thusv eliminating the necessity of further external heat application;

, moved in a cloc within chambers ll and 48 is maintained sufllcientlyhigh to cause a slight leakage of dehumidified air into the impregnatingchamber 59 and into the first heating chamber 29. This pressuresubstantially prevents fumes, emitted by the hot bitumen solution, fromentering the upper chambers and also substantially prevents the air,that is laden with the evaporated moisture in compartment 23, fromcontacting the dehydrated aggregate prior to impregnation thereof. A further advantage is that the aggregate on belt 51 is in contact withdehumidifled air prior to immersion in the vat 63. 7

From the foregoing it should be observed that from the time theaggregate has been heated and dehydrated until after it has beenimpregnated temperature of the aggregate. is substantially above thetemperature of the impregnating solution, the drop in temperature of theaggregate, when entering the colder solution, creates a vacuum withinthe pores of the aggregate particles to substantially increase theinfusion of the solution into the said particles.

After the aggregate has been impregnated, or I treated, it is dischargedby belt 51 onto a chute 95 which terminates above an air duct 61 in theside wall of the chamber II.

In order to remove all aggregate particles. and solution from belt 51 abattery of revolving brushes II are provided. The brushes l'l revolve ina direction opposite to the direction of rotation of the belt 51 andtherefore brush oil any particles and compound that adhere to the belt 551. These' particles are preferably directed into the mass of fallingaggregate on chute 65 by bame plate 19. i

A fan 69 is provided to blow air into the chamber II through the airduct 61. A supply box 13 is disposed above the duct 51 and carries asupply of dust such as mineral dust, lint or finely divided bitumnouscompound. The box 13 communicates with the air duct 61 sothat a suctionaction is set up by the air stream in the duct that draws the dust intothe air stream. Thus the blast emitted from the duct 61 is substantiallya blast of suspended dust particles which adhere to and thereby coat thefalling aggregate particles. The aggregate, after being coated, fallsupon a belt 15 which moves counterclockwise within the chamber.

An exhaust fan 16, disposed at the opposite end of chamber II isprovided to draw the surplus' dust through a suitable separator (notshown) whereby the surplus dust is recovered.

The fan 15 is preferably adjustedto maintain wan "W i u llgmitl inwthecha L, W I which belt is sill it y lr'wis 'e ion. A required number oicoils are disposed within chamber-ll and unused as a means for carryingcirculating refrigerant within the chamber 9! thereby. caus-L apparatus(not shown) is used to supply the refrigerant to the coils 95.

ber. 8| on the belt 89, the finished and treated product is dischargedtherefrom. by a chute 91 to a supply pile or truck.

Preferably all of the belts in the plant can have their sprocketssuitably geared together "and driven by a single power plant.

The walls of all the chambers are preferably insulated, as at 99, toreduce conduction of heat from one chamber to another and also tominimize the heat losses.

Preferably one truck carries three plants" I substantially similar tothe one previously ex plained. These three plants are disposed side by aside and are utilized since the usual road specification requires threedifierent grade sizes of aggregate to be used. This structure may benoted in Fig. 2. Thus the truck and plant can be placed beneath bins 9|,'93, and 95 which are associated with grading screens (not shown) andthe aggregate of selected sizes may beweighed or measured by means ofdevices 91, 99 and llii and then delivered directly into the hopper 25of each plant, or the aggregate may be fed continuously into the hoppers25.

' In the present invention each size or grade of aggregate isconditioned individually. It is apparent that the larger sizes ofaggregate require higher temperatures or longer periods of heating'tojdry the same than do the smaller grades.

the present invention this selective treatment is" made possible and asa result the finished product is more uniform than when all sizes ofaggre' gate are dried together. The separately treated aggregates ofdifierent sizes or grades are e mixed preferably after they have beensubiected to the dusting operation. fl

The bins, such as 9!, 99 and 95, used iii o'iine''" tion with thegrading screens are standard eiiu ment at any quarry or gravel pit an" afore, usually available wherever th is to be used.

Fig. 3 is a flow chart showing th in the process of aggregate trea't'mtit. of these steps may be eliminated und conditions. For example,chamber is not always necess" ture reduction chamber may likewi undercertain conditions? Iii erable to supply dehumiditle'd in chamber orchambers i an chamber, or if dehumidified air is not supplied tomaintain the tefil'fieratde sp the aggregate substantially above 'hconuensatioa temperat e of the After the aggregate passes through thecham- Irv izneretrom until gate must, under any set of conditions, beheated in the first chamber 23 and then immediately impregnated beforebeing cooled to a temperature where reabsorbtion of moisture ispossible. The features of the invention lies in preventing the driedaggregate from absorbing any atmospheric moisture before the same isimpregnated or treated with treating compound.

The present apparatus design is well adapted to meet all variablerequirements of the industry. Preferably the plant is built in unitswhich are suitably fastened together and which may be turned end for endto accommodate any number of combinations of the aforementionedchambers. In this manner if one chamber is not desired it may .beremoved without disturbing the efficiency of operation of the remainingportions of machine. This flexibility of construction also facilitatesfactory production of the machines.

It is to be understood that the term aggregate as used herein issufhciently broad to embrace any of the usual materials used, forexample, any

type of petrological substance, such as rock,

gravel or sand, or such substances as slag, cinders or coke breeze etc.inbefore described process will successfully weatherproof thesematerials.

.In general, the weatherproofed material made by this process may beutilized in the building of roads, as a basic ingredient inthe-compounding of asphaltic concrete or other compositions. Theweatherproofed product may be used in either the hot mixed-hot laid roadcomposition or the cold mixed-cold laid compositions, or in acombination of the two; The present product has 7 what may be termed, a"prime coating" thereon of compounds such as a bituminous compound,which compound is impregnated by infusion or imbibition into every poreand crevice of the usually cellular structure of the material, to morecompletely, bind the compound to the particle. In this manner thecompound substantially fills the pores and crevices of the aggregatewith bitumen and thereby actually prevents any subsequent' entry orabsorbtion of moisture therein. Therefore, the present treated aggregateis actually weatherproofed and cannot absorb moisture, neither is thereany moisture within thev all moisture therefrom; reducing thetemperature of the heated aggregate by causing relatively cooldehydrated air to pass over. the same; and then causing the driedaggregate to be impregnated with a suitable weatherprooflng agent.

2. The method of conditioning aggregate fo weatherprooiing the same,which comprises,

, heating the aggregate to eliminate substantially all moisturetherefrom; reducing the temperature It is apparent that the hereableweatherprooflng agent; and then coating the impregnated aggregate with asuitable mineral dust; and then mechanically chilling the impregnatedaggregate to a temperature below the volatilization temperature oftheweatherproofing agent. I

3. A unitary machinefor conditioning aggr gate for weatherprooflng thesame, comprising a plurality of chambers; means associated with one ofsaid chambers for heating aggregate therein; means associated with asecond chamber for sup- D plying relatively cool, dehumidifled airthereto;

means associated with a third chamber for treating the aggregate withinthe third chamber with a suitable weath'erproofing agent; and means forprogressively advancing the aggregate through said chambers in the ordernamed.

4. A unitary machine for conditioning aggregate for weatherproofing thesame, comprising a plurality of connected chambers; means associatedwith one of said chambers and adapted to heat the chamber for dryingaggregate therein; means associated with a second of said chambers andadapted to treat the aggregate, therein with a suitable weatherproofingagent; means associated with a third chamber, said last means beingadapted to chill the chamber; and means associated with the chambers forprogressively advancing the aggregate through said chambers in the ordernamed.

5. In an apparatus for weatherprooflng aggregate and the like, having incombination, means for dehydrating the aggregate and means forimpregnating the aggregate with a suitable weatherproofing agent; meansforming an enclosed conveyor for moving the aggregate from thedehydrating means to the impregnating means; and means for forcingdehumidified air into the enclosed conveyor and over the aggregatetherein.

6. In an apparatus for weatherproofing aggregate and the like, having incombination, means for heating the aggregate and means for impregnatingthe aggregate with a suitable weatherproofing agent; means for movingthe aggregate from the heating means to the impregnating and a chamberhaving means for impregnating 1 the aggregate with a suitableweatherproofing agent; .a chamber intermediate the first two mentionedchambers; means for forcing dehumidified air into the last mentionedchamber; and means for conveying the aggregate through said chambers.

8. The method of conditioning aggregate for weatherprooflng the same,which comprises, causing the aggregate to be heated for a predeterminedtime; agitating the aggregate, and again heating the same for apredetermined period to eliminate substantially all moisture therefrom;next subjecting the hot aggregate to relatively cool dehydrated air forreducing the of the heated aggregate by-causing relatively cool Idehydrated air to-pass overthe same; causing the temperature of theaggregate and then impregnating the aggregate, while subjected to thedehydrated air with a suitable weatherprooflng agent.

' JAMES ELLIOTT HALL.

